Rheostat.



No. 758,164. PATENTED APR; 26, 1904.

. W. 0. YATES.

' RHEOSTAT. APPLICATION FILED AUG. 16, 1901.

N0 MODEL.

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"cums finer; e0, wom-u-mo. mam-seven n c UNITED STATES Patented April 26, 1904.

PATENT OFFICE.

WILLIAM C. YATES, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RHEQSTAT.

SPECIFICATION forming part of Letters Patent No. 758,164, dated April 26, 1904.

Application filed August 16, 1901. Serial No. 72,228. (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM (J. YATES, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Rheostats, of which the following is a specification.

This invention relates to rheostats; and its object is to provide improved means for obtaining a minute subdivision of the resistance in order to allow very close regulation of s the current. It has been proposed to accomplish this with a comparatively small number of contact-points by dividing the resistance into two parts and providing means for switching one part into circuit between'any two points of the other part.

This invention consists in improved means for effecting this result.

In the accompanying drawings, Figure 1 is a front elevation of a rheostat face-plate embodying my improvements, the operatinghandle being removed. Fig. 2 is a vertical central section thereof. Fig. 3 is a diagram of the circuit connections between a compound resistance according to my invention and an electric motor.

The plate A of insulation has a circular row of contact-points B and a centrally-pivoted rheostat-arm O, adapted to make contact with the points B, and so cut in or out the resistance-coils D in the usual manner. Adjacent to the pivot of the arm O is pivoted another switch-arm E, cooperating with a series of contact-points F, connected with the coils of a second resistance G. The two resistances D G are connected in series, the first one, D, containing some small fractional part of the wholesay oneseventhbut divided between a large number of points, the other resistance, G, containing, say, six-sevenths of the whole and having buta few subdivisions. My improvement consists in the means whereby the two arms are moved. In Figs. 1 and 2 the arm O is provided with a pin or tooth c, which once in each revolution engages with a notch in a segment 0, attached to the arm E, and carries it far enough to shift the arm from one point F to the next. This takes place during the movement of the arm C over only three or four of the points B. In the drawings there are seven points F and fifty points B, so that the entire resistance can be subdivided into three hundred and fifty parts by the alternate movements of the two arms, the arm O making seven complete revolutions and the arm E making seven intermittent steps, one at the end of each revolution of the arm C.

Fig. 3 shows in diagram the two parts D Gr of the resistance and the switch-arms O E, the former connected with one terminal of the motor P or other desired translating device. Main leads 1 2 are connected, respectively, with the resistance G and the other terminal of the motor.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. Arheostat provided withacircular range of contact-studs, resistance units between successive pairs, a brush-arm for successively engaging the studs throughout the circular path, a secondary range of greater resistance units, studs therefor, a brush-arm cooperating with the studs, and intermediate gearing by which movement of the first-mentioned arm over the contacts causes a step-by-step movement of the last-mentioned arm.

2. A rheostat provided with two ranges of contact-studs continuously connected in series relation, and means for operating the one having the larger resistance units intermittently during the operation of the other. 3. The combination of two rheostats provided with ranges of contacts between which resistance units of different sizes are connected, both said rheostats being connected continuously in series relation during the operation of the rheostat, an operating-handle, and means for cutting in successively the larger units once for each traverse of the entire range of smaller units.

4. In a rheostat, the combination with a resistance divided into two parts permanently connected in series, of a switch-arm for each part, a segment on one arm, and means for actuating said segment at the end 'of each revolution of the other arm.

5. In a rheostat, the combination with a reswitch-arm for each part, and means for arms ing a step movement of the arm controlling the larger part at the end of a definite movement of the arm controlling the smaller part.

In witness whereof I have hereunto set my hand this 14th day of August, 1901.

WILLIAM G. YATES.

WVitnesses:

BENJAMIN B. HULL, MARGARET E. WVooLLmY 

